Circuit breakers or air circuit breakers have been used in a DC circuit on railway vehicles. Other examples may be tramways or trolley buses. For example, such high speed DC circuit breakers may switch direct currents with more than 600 Volt and 5000 Ampere.
For example, in DC circuit breakers a lot of gas is created by disconnecting the switch contact better exhausted on all sides of the metal plates in the arc chute. For example, the gas is created by plastic frames on which the metal plates are placed. The plastic frames form dielectric layers between the metal plates. The arc chutes are then covered by a moulded housing. As the gas is exhausted on all sides, the circuit breaker needs a lot of place which cannot be used by other equipment. The place on the rolling stock can be limited.
In arc chute assemblies of known DC-circuit breakers, plastic frames and metal plates are alternatingly stacked upon each other, wherein the metal plates are disposed on the plastic frames. The plastic frames have a cut out such that an arc may be built up between two adjacent metal plates. The plastic frames are used to generate gas, such that the heat in the arc is quickly blown out of the arc chute and to increase the arc voltage by a change of the chemical composition of the air between the metal plates.
The arc can often move on the metal plates, such as within the cut out. However, the arc can stay at a corner of the cut out. Thus, the metal of the metal plates gets very hot at these corners and may start melting. In the worst cases, adjacent metal plates are connected to each other by melted metal.
This leads to a short lifetime of the arc chutes and a big structural dimension due to an increased distance between the metal plates to avoid a connection between two adjacent metal plates due to melted metal, and an increased number of the metal plates and plastic frames.
Known arc chutes can be heavy and have a high height. Further, the wear is important, such as at high currents, for example at currents greater than 1 kA. The wear can depend on the number of operations, the current density and the arcing time (time constant). Thus, the wear of the arc chute is not predictable. Hence, maintenance operation is difficult to plan but is nevertheless indispensable. For example, the metal or steel plates may be often checked and replaced. Further, the plastic frames may be checked as well and sometimes even replaced. Further, there is a risk of steel drop minimum between the plates, such that less voltage is built up. In some cases, the circuit breaker may not be able to be cut the next time. Further, more than 120 components can be assembled and the clearance distance may increase.
US 2001/0015879 A1 discloses a circuit breaker with two arc chute stacks parallel to each other and an inner and an outer housing in which the functional components of the breaker are located. A sidewall of the housing which is aligned in parallel to the two arc chute stacks having openings.
US2005/0263492 A1 discloses a low voltage circuit breaker for continuous current rating up to 400 amps having a pivoting member with a handle and an arc chute stack to extinguish electric arcs.